Reinforcement using undoped carbon quantum dots (CQDs) with a partially carbonized structure doubles the toughness of PVA membranes

Nano-carbon-reinforced polymer composites have gained much consideration in functional applications due to their attractive mechanical strength and cost-effectiveness. The surface chemistry and associated mechanical strength of carbon nanotubes (CNTs), graphene, and other carbon derivative-based nanocomposites are well understood. While CQDs are considered emerging carbon derivatives, their surface chemistry, unique physio-chemical properties, and dispersion behavior in polymers are yet to be explored. Therefore, in this work, CQDs with different structures were synthesized from lemon pulp and urea, and their rheology and mechanical strength were studied in the PVA matrix. The surface chemistry and structure of CQDs were controlled using different solvents and reaction temperatures, respectively. CQDs possessed a circular shape, with a size of